Next time you’re driving somewhere, just pick a pedal and push it to see if it has the desired effect. If you go faster that’s the gas. If you go slower that’s the brake. If neither of them do anything try switching the engine on. You might need to fiddle with the gearstick as well, one of them makes you go backwards, the others are forwards. Just experiment and you’ll figure it out.

Preferably well away from any othe traffic.